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Ab Initio Characterization of the Weakly Bound Anions ClOO- and ArCl-



Karl K. Irikura


Experimental studies of the energetics and vibrational spectrum of the chloroperoxyl radical, ClOO, are contradictory. The most recent experiment accessed the radical by photodetachment of the corresponding anion, ClOO-. The present study uses both multi- and single-configuration ab initio methods to characterize various structures and spin-states of the ion, for the first time. The calculations support the recent experimental description of ClOO- as a weakly bound complex, not a chloroperoxide anion. Three local minima were found on the triplet-state potential energy surface; the lowest has an average equilibrium Cl-O distance of 361 pm and equilibrium Cl-O-O bond angle of 102 . The vibrational ground state probably has C2v symmetry, resulting in the designation 3B1 for the electronic ground state. The calculated binding energy is D0(Cl--O2) = 466 10 cm-1 (5.57 0.12 kJ mol^-1^). Small Franck-Condon factors are expected for adiabatic electron detachment, in conflict with the vertical process inferred from the experiments. Thus, the experimentally determined electron affinity is only an upper limit. Companion calculations on ArCl- [D0(Cl--Ar) = 489 cm-1] support both experimental estimates [D0(Cl--Ar) = 494 5 cm-1] and the present calculations for ClOO-.
International Journal of Mass Spectrometry


ab initio, anion, C1O<sub>2</sub>, ClOO, photoelectron spectroscopy, quantum chemistry, van der Waals


Irikura, K. (2003), Ab Initio Characterization of the Weakly Bound Anions ClOO- and ArCl-, International Journal of Mass Spectrometry (Accessed July 22, 2024)


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Created August 1, 2003, Updated February 17, 2017